CAJ | 학술논문

研究了MnO_2离子筛的制备、表征及其提锂性能.通过控制低温水热合成反应条件制备了4种不同晶相的一维纳米MnO_2,进一步用浸渍法制备了Li-Mn-O三元氧化物前驱体,并经酸处理后得到对Li~+具有特殊选择性的离子筛.用XRD、吸附等温线、吸附动力学及pH滴定等手段对产物的晶相结构和Li~+吸附性能进行了研究.结果表明,SMO-b和SMO-d离子筛的Li~+平衡吸附量符合Freundlich吸附等温方程.反应物浓度对MnO_2不同晶面的生长速率有不同的影响,但(NH_4)_2SO_4对吸附容量并无提高.吸附速率方程符合一级动力学Lagergren方程.MnO_2离子筛Li~+的吸附量远远高于Na~+.
연구료MnO_2리자사적제비、표정급기제리성능.통과공제저온수열합성반응조건제비료4충불동정상적일유납미MnO_2,진일보용침지법제비료Li-Mn-O삼원양화물전구체,병경산처리후득도대Li~+구유특수선택성적리자사.용XRD、흡부등온선、흡부동역학급pH적정등수단대산물적정상결구화Li~+흡부성능진행료연구.결과표명,SMO-b화SMO-d리자사적Li~+평형흡부량부합Freundlich흡부등온방정.반응물농도대MnO_2불동정면적생장속솔유불동적영향,단(NH_4)_2SO_4대흡부용량병무제고.흡부속솔방정부합일급동역학Lagergren방정.MnO_2리자사Li~+적흡부량원원고우Na~+.
The paper presents preparation and characterization of the MnO_2 ion sieve for recovering lithium from aqueous media.Different MnO_2 polymorphs,produced by low temperature hydrothermal oxidation of Mn~(2+)by S_2O_8~(2-)with or without(NH_4)_2SO_4 at 393 and 423 K,were employed to prepare 4 MnO_2 based ion sieve adsorbents.The structure characteristics,adsorption and ion-exchange properties of the adsorbent were studied by XRD analysis and experimental runs for the Li~+ isotherms,adsorption kinetic data and the effect of initial pH value on the capacity.The capacities of SMO-b and SMO-d adsorbents for Li~+ vs.its equilibrium concentration data were well fitted by the Freundlich adsorption isotherm model.The relative capacity data suggest that(NH_4)_2SO_4 is not necessary for the oxidation.The first order reaction kinetics model is adequate to predict the Li~+ concentration decay curves of the kinetic runs.The MnO_2 based ion sieve adsorbent exhibits an order of magnitude higher capacity for Li~+ than for Na~+.